Compared to other everyday risks we readily accept, the overall risk to us from branches or trees falling is extremely low.
Our annual risk of being killed or seriously injured is less than one in a million. That's so low, we're at greater risk driving on about a 400km/250mi round trip to visit friends for a weekend than from branches or trees falling over an entire year.
Driving for about 400km/250mi = 1 micromort, which is a one in a million chance of dying.
Given the number of trees we live with, and how many millions of us pass them daily, being killed or injured by a tree is a rare event. A rare event that usually happens during severe weather.
Tree risk is about the risk from branches or trees falling. It has three variables to it. Two likelihood variables and one consequences variable.
1) The likelihood of a branch or tree falling
2) The likelihood of someone or property being there when the branch or tree falls
3) The consequences of the tree part hitting someone or property
What is the risk from branches or trees falling?
Compared to other everyday risks we readily accept, the overall risk to us from branches or trees falling is extremely low. Our annual risk of being killed or seriously injured is less than one in a million. That's so low, we're at greater risk driving on about a 400km/250mi round trip to visit friends for a weekend than from branches or trees falling over an entire year. Given the number of trees we live with, and how many of us pass them daily, being killed or injured by a tree is a rare event; one that usually happens during severe weather.
Duty holders who don't have a strategy explaining how they manage the risk from tree failure are vulnerable to legal claims or enforcement action. Even though we know the overall risk of death or serious injury from tree failure is extremely low, a number of recent Coroner's Inquests from around the world have highlighted why having a strategy in place is so important.
Death on the highway, from the Arboricultural Association's Arb Magazine (Summer 2020), takes a closer look at the importance of Tree Risk-Benefit Management Strategies to the duty holder.
A case of rough Justice?
Here's a LinkedIn article about the landmark Cavanagh v Witley Parish Council Judgment. It explores the gulf between reasonable, proportionate, and reasonably practicable tree risk management and assessment, and expert evidence in some UK court Judgments.
We now have a Cavanagh v Witley Parish Council Update
Every summer, when we get long hot dry periods, concern is often raised about the risk from Summer Branch Drop (SBD). Fear not. We’ve got the risk management of SBD covered for you in our free Summer Branch Drop (SBD) Guide.
Is this SBD?
In brief, the overall risk from SBD is mind-boggling low. What that means is there’s no need to fret about putting up signs, or fencing, or pruning, unless you have a tree that’s a repeat offender.
Have a look at our Risk Management page for lots more free and handy common sense tree risk management advice and help.
When a tree might be 'dangerous'*, it'll usually have obvious features (not tree defects) that you can't help but notice.
To help you spot trees that might be dangerous, here's an illustrated Obvious Tree Risk Features Guide for you to download.
We're a not-for-profit and this is released under a creative commons licence, so we're more than happy for you to share it around.
*Dangerous = where the risk is not Acceptable or Tolerable.
'Tree Defect' no longer appears in any of VALID's Tree Risk-Benefit Management Strategies.
Want to know why we're 'ditching the defect' here, and the App is going to have a ? added to D for DEFECT? Click the link to this short article to find out.
Taking the 'Defect' out of tree risk-benefit management strategies
Most of the research into ‘Tree Architecture’ (Arboritecture) is from France and Canada. That means it’s published in French, which many of us can’t read. This piece by Tom Joye, in the UK’s Arboricultural Association’s Arb Magazine, is a great introduction to the world of Tree Architecture, and what it can reveal about the ‘development stage’ of a tree. It’ll have you look at growth and epicormic growth in a different way.
Following several requests, there’s now a What is VALID? about on one side of paper.
To make good decisions (about tree risk) means that we have to have confidence in what we do know and what we don't know. This double-header about confidence is a great listen from the BBC World Service.
It's probably not much of surprise to find out there's very little overlap between confidence and competence; how good people think they are, and how good they really are.
Confidence: Why it misleads us
But confidence can also be a force for good. Here's how.
Confidence: How it can help us
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